<head><title></title><script type="text/javascript">... var classification_names = [["一年一班","一年二班"],["二年一班"],["三年一班"],["四年一班"]]; var classificaiton_ids = [[1,2],[3],[4],[5]]; function class_onchange() ...{ //删除前面所有分类 var classifications = document.getElementById("classifications"); var count=classifications.options.length; var delCount = 0 ; while(delCount < count) ...{ classifications.options.remove(i); delCount++; } //获得所选班级id var classid=document.getElementById("class").value; //获得id班级所有分类名 var thisClassifcationNames=classification_names[classid]; if(!thisClassifcationNames) ...{ return; } //获得id班级所有分类id var thisClassifcationIds=classificaiton_ids[classid]; if(!thisClassifcationIds) ...{ return; } //设置该班级分类选项 var nullOption = document.createElement("option"); nullOption.text="--请选择分类--"; nullOption.value=""; classifications.options.add(nullOption); classifications.value=""; for(var i=0;i<thisClassifcationNames.length;i++)...{ var option = document.createElement("option"); option.text=thisClassifcationNames[i]; option.value=thisClassifcationIds[i]; classifications.options.add(option); } }</script></head><body>班级<select id="class" name="class" onchange="return class_onchange()" > <option value="-1" selected="selected">请选择年级</option> <option value="0">一年级</option> <option value="1">二年级</option> <option value="2">三年级</option> <option value="3">四年级</option></select>分类<select id="classifications" name="classifications"> <option value="-1" selected="selected">请选择班级</option></select></body>